In popular culture, Tarot is generally portrayed as part of the fortune-teller's toolkit. Divination is primary, and Michael Dummett et al. tell us that before Tarot started to be used for that purpose the decks were used in games of chance, much the way modern playing cards are.
I doubt most Tarot readers, even the ones who may think they're "a little bit psychic," believe the cards possess special powers. Their value, rather, lies in a kind of provocation, in bringing to the surface critical events, personalities, and relationships of importance to the customer, or subject. They believe there is value in reading the cards so as to make the subject conscious of people and issues that might escape notice otherwise.
This use of the cards is different from fortune-telling, because it doesn't claim to predict anything with certainty but rather affords an opportunity to interpret a cluster of notions surrounding events, personalities, or relationships that are of importance to the subject.